Run db migrations on start

We should force db migrations to run on every start. This will minimize
the impact of breaking migrations in future. While it may causes some
issues with the next start since CodiMD won't start when the migrations
fail.

Signed-off-by: Sheogorath <sheogorath@shivering-isles.com>

package.json

@@ -11,7 +11,7 @@
     "dev": "webpack --config webpack.config.js --progress --colors --watch",
     "build": "webpack --config webpack.production.js --progress --colors --bail",
     "postinstall": "bin/heroku",
-    "start": "node app.js",
+    "start": "sequelize db:migrate && node app.js",
     "doctoc": "doctoc --title='# Table of Contents' README.md"
   },
   "dependencies": {